Thermostat



(No Model.)

C. BURGHER.

THERMOSTAT.

-Patented Deo. l5, 1896.

Inh/ENTER.`

WITNaEEE-L PWT 'Y UNITED STATES PATENT OEEICE.

CHARLES BURGHER, OF NEVTON, MASSACHUSETTS, ASSIGNOR TO THE BOSTON AUTOMATIC FIRE ALARM COMPANY, OF PORTLAND, MAINE.

THERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 573,134, dated December 15, 1896.

Application filed August 8,1896. Serial No. 602,137. (No nioclel) [o all whom t may concern:

Be it known that I, CHARLES BUEGHEE, residing in Newton, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Thermostats, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to thermostatic instruments of that class now commonly employed in automatic fire-alarm systems, and has for its object to provide a thermostat which is more effectively protected from mechanical injury without decreasing its sensitiveness and efficiency.

In accordance with this invention the active members of the thermostat are located within a shell or casing consisting of a body portion, preferably circular in form, and provided at one end with a reticulated or foraminous bottom and at its opposite end with a cap or cover attached to the said body, as will be described, so as to afford free circula tion of air through the instrument. The cap or cover referred to is preferably provided with a depending lip or flange, which forms a guard for a purpose as will be described. These and other features of this invention will be pointed out in the claims at the end of this specification.

Figure l represents in elevation a thermostatic instrument embodying this invention 5 Fig. 2, an under side view of the thermostat shown in Fig. l; Fig. 3, an under side view of the instrument shown in Fig. l with the foraminous bottom broken away; Fig. 4, a top or plan view of the instrument shown in Fig. l with the cover or cap removed; and Fig. 5, a section on the line 5 5, Fig. Q, looking down.

In accordance with this invention the therinostatic instrument consists, essentially, of a hollow shell or casing, which may be of any suitable or desired form, preferably circular, and composed of a ring or body portion a, having secured to or forming part of it a re ticulated or foraminous bottom a', herein shown as provided with circular openings ai) in the greater portion of its surface.

The hollow shell or casing contains within it the active members of the thermostat, which members may be of any suitable or desired construction, but preferably that commonly used in the well-known Watkins thermostat, and consisting of an expansible strip a5, provided in the present instan ce with two coils, the said strip being secured at one end to the body a, as by screws a a7, but suitably insulated therefrom, as by pieces as a9 of insulating material. The free end of the eX- pansible strip d5 cooperates with a contact point or screw am, carried by a terminal plate, bar, or strip als, which is fastened to the body a, as by screws am a, insulated from the said body by pieces al all of insulating material. The body a in line with the contact-screw uw is provided with an opening als, through which access may be had to the said screw if it is desired to adjust the same with relation to the strip c5 or if it is desired to remove the same for cleaning or other purposes.

The body or ring d is provided with a cap or cover b, which is supported above the said ring, preferably by a spider or open frame, preferably composed of a raised center portion b and downwardlynclined arms b2, attached at. their ends to the ring or body c. The cap I) may be secured to the shell or casing, as herein shown, by a tube or sleeve if, preferably split longitudinally and having its ends turned outward, as at h6 D7, (see Fig. 5,) the said tube serving also to secure the bottom a to the shell a. The cap Z7 may and preferably will be loose on the tube or sleeve h5, so as to be free to turn thereon, and preferably one or more washers bs will be interposed between the said cap and spider. The cap l) is preferably made larger than the ring or body c and is preferably provided with a depending annular iiange bw, extended down below the upper edge of the body to form a guard and prevent the entrance into the body of foreign matter, such as paint, whitewash, &c.

The Vinstrument may be secured to the ceiling or wall of a building by a screw c, extended through the tube or sleeve h5. In opera tion the foraminous bottom a exposes the operative or active members of the instrument to the act-ion of the air, and at the same time protects them from mechanical injury, and is especially effective against the entrance IOO of paint, whitewash, the., when the instrument is brushed over by the carelessness of painters and Whitewashers, i'or it will be seen from an inspection of Fig. l that in the act of drawing a brush of paint or Whitewash over the instrument the brush Will irst strike the lower edge of the body or ring a before it comes in contact with the foraminous botton c', and as a result the greater portion of the paint or Whitewash will be removed from the brush, so that what remains on the brush will not Wholly ll the pores or openings Co2 of the bottom d', and that quantity of paint or whitewasli which may adhere to the bottom Will, when dry, contract and leave the openings a2 uncovered and of substantially the same open condition as before the paint or whitewash Was applied.

The foraminous bottom ailords a protection for the operative parts of the instrument without detracting from the sensitiveness oi the instrument, but in order to increase the sensitiveness of the instrument the body or ring a is left substantially open at its opposite end, and the cover b is separated therefrom for the free circulation of air through the in* stru ment.

In practice the instrument included in a circuit represented by the line-Wires d d', connected to the binding-screws al @15. I prefer to make the casing or shell and its cap of meta-l, but they may be made of an57 suitable material.

If desired, the portion of the bottom a covering the point of contact of the strip of and screw aw may be left solid or imperforate, as shown in Fig. 2, or it may be provided With openings or pores,as indicated by dotted lines.

I claiml. In a thermostatic instrument, the combination With a shell or casing provided with a reticulated or foraminous bottom having a plurality of holes or openings and provided at its opposite end with a spider or open frame having a raised center portion, and a cap or cover attached to and supperted above the said easing or shell by the said raised center portion of the said spider to leave an air space or passage, and active members secured Within the said casing or shell, substantially as described.

2. In a thermostatic instrument, the combination of the following instrumentalities, a shell or casing a opened at its opposite ends, and provided at one end With a spider having a raised center portion, a foraminous bottom a detachable from the casing a, a cover Y) supported on the raised center portion of the spider and provided with a depending flange outside of said casing a, a tube b5 extended through the foraminous bottom, the spider and the cap and acting to secure the said bottom and cap to the shell, and active members Within the shell and protected by the foraminous bottom, substantially as described.

In a thermostatic instrument, the combination of the following instrumentalities, a casing or shell composed of a ring or body (r` having a foraminous bottom, and a spider at its opposite end, a cap for the opposite end of said shell and provided with a depending iange forming an air-space with the body a, a hollow connection joining said cap to said shell and spider, and active mem bers secured Within said casing, substantially as described.

In testimony whereof I have signed my name to this specication in the presence oi' two subscribing witnesses.

i CIIAS. BURGIIICR.

l/vitliesses:

JAS. II. CHURCHILL, J. MURPHY. 

